--- a/WinWorkstation.st	Tue Mar 20 22:04:49 2007 +0100
+++ b/WinWorkstation.st	Wed Apr 04 16:18:07 2007 +0200
@@ -9,14 +9,17 @@
  other person.  No title to or ownership of the software is
  hereby transferred.
 "
+'From Smalltalk/X, Version:5.3.5 on 04-04-2007 at 15:55:25'                     !
+
 "{ Package: 'stx:libview' }"
 
 DeviceWorkstation subclass:#WinWorkstation
 	instanceVariableNames:'blackpixel whitepixel listOfFonts rootWin rootDC buttonsPressed
-		eventTrace eventBuffer isWin95 isWinXP'
+		eventTrace eventBuffer isWin95 isWinXP
+		lastClipboardSequenceNumber'
 	classVariableNames:'BeepDuration NativeDialogs NativeWidgets NativeWidgetClassTable
 		StandardColorValues IgnoreSysColorChanges IgnoreFontChanges
-		SystemColorValues ClipBoardObject'
+		SystemColorValues'
 	poolDictionaries:''
 	category:'Interface-Graphics'
 !
@@ -8517,8 +8520,87 @@
 
 !WinWorkstation methodsFor:'clipboard'!
 
+getClipboardObjectFor:drawableId
+    "answer an arbitrary object from the clipboard, or nil,
+     if there is no data that we are able to handle (decode)"
+
+    |currentSequenceNumber|
+
+    currentSequenceNumber := self getClipboardSequenceNumber.
+    lastClipboardSequenceNumber ~= currentSequenceNumber ifTrue:[
+	"copyBuffer is invalid, fill it from the windows clipboard.
+	 Even if we could not decode the windows clipboard,
+	 we intentionally set the copyBuffer to nil to get a consistent
+	 behavior."
+	copyBuffer := self getClipboardData.
+	lastClipboardSequenceNumber := currentSequenceNumber.
+    ].
+    ^ copyBuffer
+!
+
+getClipboardText:selectionBufferSymbol for:drawableId
+     "get the contents of the clipboard and answer a String,
+      or nil, if there is no data that we can handle (decode)."
+
+    |currentSequenceNumber|
+
+    currentSequenceNumber := self getClipboardSequenceNumber.
+    lastClipboardSequenceNumber ~= currentSequenceNumber ifTrue:[
+	"copyBuffer is invalid, fill it from the windows clipboard.
+	 Even if we could not decode the windows clipboard,
+	 we intentionally set the copyBuffer to nil to get a consistent
+	 behavior."
+	copyBuffer := self getClipboardData.
+	lastClipboardSequenceNumber := currentSequenceNumber.
+    ].
+    ^ self copyBufferAsString
+!
+
+setClipboardObject:something owner:drawableId
+    "store an arbitrary object into the clipboard.
+     Since we currently support only text, any other object
+     is stored only in our local copyBuffer and not made available
+     to other applications."
+
+    something isString ifTrue:[
+	self setClipboardText:something owner:drawableId.
+	^ self
+    ].
+    something isStringCollection ifTrue:[
+	self setClipboardText:something asString owner:drawableId.
+	^ self
+    ].
+
+    "copyBuffer is valid until the clipboard sequence number increases,
+     because new data has been put into the clipboard"
+    lastClipboardSequenceNumber := self getClipboardSequenceNumber.
+
+    "Created: / 13.7.1999 / 13:30:37 / cg"
+    "Modified: / 30.1.2000 / 11:59:41 / cg"
+!
+
+setClipboardText:something owner:drawableId
+    "store some text into the clipboard"
+
+    |result|
+
+    result := self setClipboardData:something asString string.  "take care of StringCollections"
+
+    "as long as the sequence number doesn't change, our copyBuffer is valid"
+    lastClipboardSequenceNumber := self getClipboardSequenceNumber.
+    ^ result.
+
+
+    "Created: / 13.7.1999 / 13:36:43 / cg"
+    "Modified: / 30.1.2000 / 12:12:57 / cg"
+! !
+
+!WinWorkstation methodsFor:'clipboard-private'!
+
 getClipboardData
-    "caveat: for now, only Text is supported"
+    "get the contents of the windows clipboard.
+     Answer a string on success or nil otherwise.
+     Caveat: for now, only Text is supported"
 
 %{
     HANDLE hClip;
@@ -8641,36 +8723,41 @@
 %}
 !
 
-getClipboardObjectFor:drawableId
-    ^ ClipBoardObject
-
-    "Modified: / 30.1.2000 / 02:26:47 / cg"
-!
-
-getClipboardText:selectionBufferSymbol for:drawableId
-    ^ self getCopyBuffer.
-!
-
-getCopyBuffer
-    "return the copyBuffers contents."
-
-    |clip|
-
-    ClipBoardObject notNil ifTrue:[
-	^ ClipBoardObject
-    ].
-
-    (clip := (self getClipboardData)) notNil ifTrue:[
-	^ clip
-    ].
-    ^ copyBuffer
-
-    "Created: / 13.7.1999 / 13:15:35 / cg"
-    "Modified: / 30.1.2000 / 12:01:13 / cg"
+getClipboardOwner
+    "answer an handle telling us, who owns the clipboard."
+
+%{
+    HANDLE hWnd;
+
+    hWnd = GetClipboardOwner();
+    RETURN(__MKEXTERNALADDRESS(hWnd));
+%}
+
+   "
+	Screen current getClipboardOwner
+   "
+!
+
+getClipboardSequenceNumber
+    "answer the sequence number of the clioboard.
+     Each time, the keyboard is changed, the sequence number is incremented."
+
+%{
+    DWORD sequenceNumber;
+
+    sequenceNumber = GetClipboardSequenceNumber();
+    RETURN(__MKUINT(sequenceNumber));
+%}
+
+   "
+	Screen current getClipboardSequenceNumber
+   "
 !
 
 setClipboardData:aString
-    "caveat: for now, only Text is supported"
+    "Set the contents of the windows clipboard.
+     Answer true, if the operation succeeded, false otherwise.
+     Caveat: for now, only Text is supported."
 
 %{
     HANDLE hClip;
@@ -8790,25 +8877,6 @@
     }
 %}.
     self primitiveFailed.
-!
-
-setClipboardObject:something owner:drawableId
-    something isString ifTrue:[
-	self setClipboardText:something owner:drawableId.
-	^ self
-    ].
-    ClipBoardObject := something.
-
-    "Created: / 13.7.1999 / 13:30:37 / cg"
-    "Modified: / 30.1.2000 / 11:59:41 / cg"
-!
-
-setClipboardText:something owner:drawableId
-    ClipBoardObject := nil.
-    ^ self setClipboardData:something
-
-    "Created: / 13.7.1999 / 13:36:43 / cg"
-    "Modified: / 30.1.2000 / 12:12:57 / cg"
 ! !
 
 !WinWorkstation methodsFor:'color stuff'!
@@ -16985,7 +17053,7 @@
 !WinWorkstation class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libview/WinWorkstation.st,v 1.341 2007-03-14 15:34:54 stefan Exp $'
+    ^ '$Header: /cvs/stx/stx/libview/WinWorkstation.st,v 1.342 2007-04-04 14:18:07 stefan Exp $'
 ! !
 
 WinWorkstation initialize!